Spark-plug and ignition tester



W. S. WITTER.

SPARK PLUG AND IGNITION TESTER.

APPLICATION FILED FEB. I5, I919.

Patented July 26, 1921.

a lmmm hlflh/ifler UNITED STATES PATENT OFFICE.

WILLIAM S. WITTER, OF DAVENPORT, IOWA.

SPARK-PLUG AND IGNITION TESTER.

Specification of Letters Patent.

Patented July 26, 1921.

To whom it may concern:

Be it known that 1, WILLIAM S. WIT'IER, a citizen of the United States, residing at Davenport, in the county of Scott and State of Iowa, have invented certain new and useful Improvementsin Spark-Plug and Ignition Testers, of which the following is a specification, reference being had to the accompanying drawings.

This invention relates to means for test ing spark plugs, and particularly to that class of devices in which a holder of 1nsulating material is used having (11S30S61l therein a spark gap, the terminals 0 this spark gap being adapted to be operatlvely connected to the spark plug or other. part to be tested, and the holder being formed so that an observer may look through the holder at the spark gap inclosed therein to determine if the spark is jumping across the gap properly and thus determine the elec trical condition of the spark plug or other element being teste a u I The general object of my invention 1s to provide a tester of this character which is very simple in construction, very compact, and which is adapted to be used not only for testing ignition circuits and spark plugs or other high tension circuit.

A further objectis to provide a ClGVICG OT this character including a conductor which is pivotally connected to the insulating body so that it may be turned into a positionto form an extension from the body and which is adjustable into a plurality of angular positions relative to the body so that the conductor may be applied to the part belng tested, even though this part may be in a place which wouldbe ordinarily inconvenient to connect with. i

A further object is to provlde aconstruction of this character wherein only one condoctor is used and wherein a switch is provided which, when open, permits the device to be used for testing the insulating quallties of the spark plug porcelain and which, when closed, permits the device to be used for testing the condition of the electrodes of the spark plug. 1

Other objects have to do with the details of construction and arrangement of parts, as will appear in the following description.

My invention is illustrated in the accompanying drawings, wherein Figure 1 isa side elevatlon of a spark plug tester;

'20 and the rod 21 Fig. 5 is a side elevation of the tester in use.

Referring to these figures, 10 designates a older or body which is formed of insulatmg material, such as fiber, ebonite, porcelain, or any other suitable material having insulating qualities, and midway of its ends, this body 10 is formed with a lateral extens10n 11. Preferably, the body with the extension 11 is rectangular in cross section'but above and below the extension, the body 10 1s circular or tubular in cross section. 1 The body is formed with a longitudinally extending bore 12 leading from one end, and the wall at the open end of this bore is rounded, as at 13. At its opposite end, the body is closed and formed with a laterally or diametrically extending socket 14. Disposed within the bore 12 and resting on the closed end of the body is a metallic member 15, which may be made of iron rod or other suitable metal to form a relatively large metallic body disposed at the lower end of the bore 12. he purpose of this metallic body 15 will be later stated. Attached to one end of this rod or metallic body 15, is an upwardly extending electrode 16. Disposed above the body 15 is a sleeve 17, which may be made of insulating material or metal and supported on the upper end of this sleeve is a magnifying glass or lens 18, which is held in place by a retaining ring 19 sprung into an annular recess formed in the wall of the bore 12, this re taining ring holding the lens 18 upon the sleeve 17 Extending into the socket 141 is the angular end 20 of a wire or rod 21 constituting a conductor, the free end of this rod 21 be ing formed to provide an eye 22. This rod 21 may rotate in the socket 14 upon its axis has such length that it may be turned to a position which will carry the eye 22 over the upper end of the extension 11. The extension 11 is formed with a longitudinally extending bore, the lower end of which isreduced in diameter, and disposed in this lower end is a conducting rod or wire 23, the lower extremity of which is laterally bent and pointed, as at 24, and enters a small recess formed in the rod 21 immediately opposite the axis of the angular portion 20. This rod 23 is slightly resilient and, therefore, the pointed end 24: holds the angular portion 20 of the rod 21 into the recess 14, but permits the rod 21 to be rotated upon its axis.

Extending through the lateral extension,

11 and through thewall of the bore 12 and into this bore, is an electrode 25 which is formed by bending a piece of wire upon itself, this electrode 25 being disposed in a transversely extendinghole bored through the extension 11 and being placed in this hole and then the hole being cemented so as tohold the electrode firmly in place. The upper portion of the bore which extends through the portion, 11 is enlarged and opens at the upper end of the extension and longitudinally shiftable through this enlarged portion of the bore is a switch button or Jlug 26 which is-of insulating material. crew-threaded in the lower end of this plug 26 isthe shank of a switch 27. This switch .-is formed by bending a half round wire upon itself and screw-threading the. adjacent. ends of the wire to engage within the plug 26. The wire is formed to provide a longitudinally extending slot 28 whichembraces and surrounds the electrode 25. The slot 28 is of sufficient width so as not to push or bind upon the electrode 25. A-coiled spring 29 urges the button or plug 7 26 upward andraises the switch 27. The

slot 28 is of such length, however, that when the button 26 is compressed to its full extent, the lower end of the switch 27 will contact with: the conductor 23.v Thus, electrical connectionwill beestablished between the conductor 21, the conductor 23, the switch 27, and the electrode 25, and when this electrica'l connection is established, a spark will jumpbetween the electrodes 25 and 16 at the gap, which'spark may be observed through the magnifying glass 18.

For the purpose of retaining the rod or plug 21 in -a position parallel to the length of the. body 10 and engaged therewith, I form the extension 11 in its side face with a groove 30, which is nearly circular, the

" throat of this groove being so narrow that the rod 21 can just pass through and that is all. Thus, the rod 21 will spring into this groove and will be slightly held therein against accidental detachment but may be re'adilyforced out of the groove so that the rodmay be disposed in any desired relation with the holder or body 10. The loop or eye 22 is designed, when the rod 21 is turned up in the .gIOOVe 30, to be disposed over the plug 26'andslightly engaged by this plug.

In the use of this device for testing spark plugs, the extremity of the wire or conductor 21 is to be placed on the spark plug in the same manner as with other testers of this character. It will be obvious that it does not matter what position the rod 21 may occupy with relation to the body 10, as under all circumstances it will act as a conductor. Thus, for instance, this conductor 21 may be turned up within its groove 30 and it will function properly, or it may be disposed at an angle to the longitudinal axis of the body 10, or as an extension of the body 10, but it will at all times act as the conductor for the electric current, or, with the plug 26 up, a light is seen within the tester by looking through the upper end thereof through the magnifying glass at the spark gap, then the porcelain or other insulation of the spark plug is cracked or broken, or if there should be a very large spark gap in the spark plug, so large that the spark cannot jump, then my tester will show a light or spark at the electrodes when the switch is up in the position shown in Fig. 3. In order to test the condition of the electrodes, the plug 26 is forced downward, thus closing the switch and establishing electrical communication between the rod 21, the rod 23, and the electrode 25, and then if a bright spark is seen at the spark gap, it can be understood that the spark plug is functioning properly. If no light or spark isseen at the spark gap, however, then the plug is dirty or is otherwise defective. It will be understood that when testing terminal wires, the eye 22 maybe hooked into the terminal cleat on the end of the ignition wire. Of course, under all circumstances, the eye is to be placed close to the upper rounded end 13 of the tester so that no outside light can interfere with the view of the spark within the tester. If the light produced by the spark within the tester is very dim, small or purple in color, this indicates poor ignition, due to very weak currents, sooty or oily plugs, plugs with a small s ark gap, leakyplugs, etc. If the plugs ash a bright light, then a poor light, with irregularity in the character of the light, this indicates short circuiting, or close and dirty electrodes. Not only can this device be used for testing spark plugs and ignition circuits, but it can also be used for testing for general magneto troubles, carburetor adjustments, timer action,etc. In other words, any trouble which will be indicated by the character of a spark at the electrode 16 will be indicated by this tester.

It is to be noted that in my testing device there is only one conductor 21 and that there is no ground wire or return wire and that the hand of the operator is entirely insulated from the conductors. It will, of course, be understood that this tester works with high voltage current which is obtained through an induction coil. I have found in actual practice that a spark will readily jump from the electrode25 to electrode 16 when the primary circuit of the induction 0011 is broken. Because of the fact that this is used on a secondary circuit with a high tension current, the current will flow into electrode 25, jump across the gap to electrode l6 and thence into the relatively large metallic body 15. I am aware of the fact that spark plug testers have been provided in which one electrode is connected by a conductor to a spark plug and the other electrode connected to a ground, either through a return wire or through the body of the operator, but constructions of this character are open to the objection that inasmuch as a complete circuit is provided, the spark will be short circuited more or less so that the plug will not give a full s ark. In testing spark plugs, however, on y one conductor should be used, such as is used in my construction, as otherwise the current will be split, part of the current going through the spark plug and the other part through the tester. In my tester I have no short circuit or appreciable return and, therefore, get the full spark the plug is iving at the time tested, while a very smal spark is secured in the tester, yet the magnifying glass 18 makes this spark perfectly evident to the operator.

It will be noted that the pivoted conductor 21 permits the construction to be applied to the eye, while the extremity of the conductor 21 ,is held against the spark plug or other part to be tested. This eliminates the necessity of holding the tester itself in position against the spark plug and having to bend the bod into inconvenient positions in order to o serve the spark. By my device, the operator can usually stand upright and hold the member 10 in proper position to look into it, while holding the contact 22 against the spark plug. It also permitsthe device to be used where spark plugs are difficult of 806888.

It is to beunderstood that when the switch 27 is spaced from the upper end of the wire 23, a gap is formed across which a spark will jump and which may be closed by closing the switch. Thus, this tester has practically two spark gaps. This is necessary inasmuch as the current acts d1fi'erently under diflerent conditions. A good working plug will only develop a small spark in the tester and this will only jump a small spark ga between the terminals 16 and 25, and on y if the switch 27 is closed Where the porcelain is cracked in a spark plug, or where the gap in the spark is over size, the spark will not jump, but in this condition the spark will jump both gaps in the tester with switch open andthis will show alight in the tester. Therefore,it willbe seen that the switch is practically a converter and operates in either position so that the operator can tell what part of the plug is going wrong.

I claim 1. A tester of the character described including an insulating tubular body, a conductor pivoted to said body to swing into or out of parallel relation thereto, a relatively large metallic member disposed within the body and having an electrode extending therefrom, an electrode coasting with the first named electrode but spaced therefrom to form a spark gap, and means whereby the conductor may be electrically connected to the second named electrode in all positions of the conductor.

2. A tester of the character described including an insulating tubular body, a conductor pivoted to said body to swing into or out of parallel relation thereto, a relatively large metallic member disposed within the body and having an electrode extending therefrom, an electrode coacting with the first named electrode but spaced therefrom to form a spark gap, and means whereby the conductor may be electrically connected to the second named electrode in all positions of the conductor and including a switch shiftable in one direction to establish electrical connection between the conductor and the electrode and in another position break said electrical connection.

3. A tester comprising a tubular body of insulating material, a conductor having one end pivoted to the tubular body to swing into a plurality of positions with relation thereto, a conducting member electrically engaged with said conductor in all positions of the conductor, a relatively large metallic body disposed within the insulating body and having an electrode observable through the opening in the body, a coacting electrode spaced therefrom to form a spark gap and spaced from said rod, and a switch shiftable in one direction to close an electrical connection between said rod and the second named electrode and in the other direction to disestablish said connection.

4. A tester comprising a tubular body of insulating material, the bore of the body being open at one end, a conductor swingingly connected to the tubular body, a second conductor fixed to the tubular body and at all times having electrical engagement with the first named conductor at its axis, a rela-.

tively large metallic member disposed with in the bore of the body and having an electrode, a second electrode spaced from the first electrode to form a spark gap and passing through the wall of the body, and a manually shiftable switch in one position electrically connecting the fixed conductor with the second named electrode and in another position breaking said connection.

5. A tester comprising a tubular body of secondelectrode spaced from the first electrode to form a spark gap and passing through the wall of the body, a manually shiftable switch in one position electrically connecting the fixed conductor with the second named electrode and in another position breaking said connection, and a magnifying lens disposed in the bore of the body adjacent the upper end thereof and focusing upon said spark gap.

6. Atester of the character described comprising a tubular body having a bore open at 7 one end, the body being formed of insulating material, a conductor angularly bent at one end and having said angular end rotat-ably engaged in the body opposite the open end thereof, a metallic body disposed with said bore and having an electrode, a second electrode passing through the wall of the body and spaced from the first electrode 'to form a' spark gap, and means for establishing or disestablishing electrical connection between the first named conductor and'the electrode.

7. A tester of the character described comprising a tubular body having a bore open at one end, the body being formed of insulating material, a conductor angularly bent at one end and having said angular end rotatably engaged in the body opposite the open end thereof, a metallic body disposed with said bore and having an electrode, a second elec trode passing through the wall of the body and spacedfromthe first electrode to form a spark ga and means for establishing or disestablishing electrical connection between the first named conductor and the electrode, and including a switch yieldingly held in one position by a spring, but shiftable against the spring to establish connection between the conductor and the second named electrode.

' 8. A tester comprising a bodyof insulating material formed with a bore open at one end, the body having a lateral extension and being formed. at its closed end with a laterally extending socket, a conductor having an angular end rotatably mounted in the socket, means for detachably holding said conductor in place in the socket, a metallic body disposed within said bore and having an electrode, a second electrode passing through the bore, and means for establishing or disestablishing electrical connection between the conductor and the second named electrode.

9. A tester including a body of insulating material having a lateral extension, the body being formed with a longitudinally extending bore opening at one end of the body, a conductor having an angularly bent end disposed in the socket formed in the closed end of the body, whereby the conductor may be swung into a plurality of positions, a re silient metallic rod forming a conductor extending longitudinally through said extension of the body and at its outer end being formed with a laterally bent, pointed terminal portion engaging against the conductor at its junction with its angular portion to thereby yieldingly hold the angular end of the conductor in place in said socket, a metallic body disposed within the bore and having an electrode, a second electrode passing through the wall of the body and into said extension of the body and spaced from the first electrode to form a spark gap, and 35 a switch operating in said extension oi the body to establish or disestablish electrical connection between the metallic rod and the second named electrode.

10. A tester of the character described including a body, a conductor swingingly mounted on the body for movement into or out of parallel relation thereto, the wall of the body being formed with a longitudinally extending groove into which said conductor is adapted to be received when the conductor is turned up into overlapped parallel rclation to the body.

11. A tester including a tubular body of insulating material, a conductor having an angular end, the body having a socket into which said end is disposed whereby the conductor may be swung into or out of a folded position with relation to the body, the exterior of the body being formed with a 5 longitudinally extending groove to receive said conductor when folded, and means yieldingly urging the angular end of the conductor into place in said socket but permitting its detachment therefrom.

12. A tester including a body of insulating material formed with a longitudinally extending bore, the bore opening on one end of the body, the opposite end of the body being formed with a diagonally ex- 115 tending socket, the middle portion of the body having a lateral extension and said middle portion being rectangular in cross section, a conductor having an angular portion at one end inserted in said socket 120 and at the other end formed with an eye, a resilient rod extending longitudinally through a portion of said extension of the body and having one end angularly bent and pointed to engage against the inner end of 125 the conductor opposite said angular extension thereof to thereby hold the angular end of the conductor in place within the socket,

a metallic body disposed within the bore and having an electrode, a second electrode ex- 130 tending through the wall of said bore and into position in alinement with the metallic rod but spaced therefrom, and a switch shift able through said extension of the body and including a metallic member having an elongated loop through which the second named electrode passes, said switch when shifted in one direction establishing electrical communication between the resilient rod and the second named electrode.

13. A tester including an insulating body, a metallic membersupported therein and having an electrode, a coacting electrode spaced from the first named electrode to constitute a spark gap, a movable switch member connected to the second named electrode and constituting a third electrode and mounted in said bod a conductor mounted upon the body or adjustment, and a conductor leading from the first named conductor to the switch but normall spaced therefrom to form a second spark gap, the switch being shiftable into contact with the second named conductor whereby to eliminate the second named spark gap.

14. A tester of the character described including an insulating body constituting a holder, a pair of spark points separated by a spark gap, a conductor coacting with the spark points, and a switch electrically engaging at all times with one of the spark points, said switch being shiftable to two positions, and in one position having contact with said conductor and in another po sition being spaced therefrom to form a second spark gap.

15. A tester of the character described including an insulating body forming a holder, a pair of spark points carried therein and spaced from each other to form a spark gap, a conductor coacting with the spark points, a longitudinally movable, man ually operable switch member electrically engaged with one of the spark points at all times and shiftable to two positions, in one position having contact with said conductor and in another position being spaced therefrom to form a spark gap between the switch and the conductor, and a spring urging the switch member away from the conductor.

16. A tester including an insulating body, a pair of spaced electrodes constituting a spark gap and mounted within the body and disposed at right angles to each other, one of said electrodes having a conductor extending therefrom, a conductor extending longitudinally into the body, a switch comprising a loop-shaped member embracing one of said conductors and having electrical engagement at all times with the other conductor, and a spring urging the switch in one direction, said switch having means whereby it may be manually shifted against the actlon of the spring.

17. A tester including an insulating body, a pair of spark points mounted within the body, one of said spark points having a conductor extending therefrom, a second conductor spaced from the first named conductor, and

a switch having sliding engagement with.

the first named conductor and movable into or out of contact with the second named conductor, the switch having means exteriorly of the holder whereby it may be shifted, and a spring urging the switch into spaced relation to the second named conductor.

In testimony whereof I hereunto affix my J. W. MULLEN, ALONZO M. CRISMAN. 

